The present invention relates to portable toilets of the types disclosed in U.S. Pat. No. 3,570,018, issued Mar. 16, 1971 to Sargent, et al., and U.S. Pat. No. 3,949,430, issued Apr. 13, 1976 to Miller et al., and is particularly directed to improvements in toilets of this character.
Portable toilets of the type disclosed in the cited patents are used extensively in the travel and recreational fields. Detachable holding tanks are provided which are closed in a sealed condition when the toilets are not in use. The pressure within the closed holding tank may deviate from the ambient pressure for various reasons, such as when traveling from a low to a high altitude, when chemical reaction within the holding tank occurs, and the like. Pressure differential of this nature can create problems for the user of the portable toilet. For example, if a portable toilet has been used at sea level where the atmospheric pressure is relatively high and the toilet is then transported to a recreational area in the mountains where the atmospheric pressure is relatively low, a pressure differential will have been created, because the pressure in the sealed holding tank will have remained essentially that which existed at sea level when the holding tank was closed. If a liquid, such as a chemical deodorant, for example, is now introduced into the toilet bowl for discharge into the holding tank through the valve between the toilet bowl and the holding tank, a jet-like gaseous discharge from the holding tank through the liquid in the bowl may occur as the valve blade is initially opened, causing upward spray of the liquid. Similarly, problems may occur if the contents of a holding tank are to be evacuated when the pressure within the holding tank is greater than the ambient pressure.
Efforts have been made to relieve problems associated with differentials between holding tank pressures and ambient pressures in toilets of the types disclosed in U.S. Pat. No. 3,747,130, issued July 24, 1973 to Sargent et al., and U.S. Pat. No. 4,032,996, issued July 5, 1977 to Sargent et al., but successful solutions to this problem have not been provided in portable toilets of the types wherein a detachable holding tank is utilized.